The present invention relates to a method for training a person while operating a vehicle.
The invention is applicable to different types of vehicles, in particular air vehicles such as aircraft for training pilots. Although aspects of the invention will be exemplified by describing an aircraft application, the invention can also be applied to other vehicles, such as cars, boats, trains etc. Thus, by the word “vehicles” is meant airborne vehicles, land vehicles as well as marine vehicles.
Training of pilots includes flying with heavily loaded aircraft. A modern aircraft can carry loads weighing at least as much as the weight of the empty aircraft. Therefore, such flights are expensive to perform because the engines have to run at high rating and fuel consumption is high. In addition, the high engine rating means significantly increased engine wear resulting in higher cost for engine maintenance. Furthermore, the stress levels (fatigue) of the aircraft structure are higher in a loaded aircraft resulting in a shorter life span and higher maintenance cost. Training with heavily loaded aircraft also means a flight safety hazard, in particular during the take off phase. A heavy aircraft has less margins and in case of an engine fault, a bird strike or any other incident there will be a higher risk for a catastrophic situation which could result in serious injuries among the crew.
The high cost and risk for training with heavily loaded aircraft often leads to the fact that such training is avoided and thus, the pilots receive less realistic training than desired.
Ground-based flight simulators are sometimes used for the above-mentioned training but in many aspects they cannot provide sufficiently realistic conditions.
Another type of training which provides more realistic situations is the use of airborne simulation systems used in real aircraft during flying. Such simulation systems use software for imposing power output limits on an engine for simulating an engine failure. A method for simulating an engine failure in a multiple-engine aircraft is described in US 2002/0133322. The engine failure is simulated by placing a software output limiter on one or more engines. This could be combined with fictitious gauge readings on the pilot's instrument panel. However, such a method, which only means that there is an option mode conferring an impaired performance of the engine which is usable for simulating a specific engine failure, does not support general training with heavily loaded aircraft of the type discussed above.
It is desirable to provide a method of the kind referred to in the introduction, which method makes it possible to train persons, such as aircraft pilots, to operate a vehicle during trying conditions in a realistic and safe way and at reasonable costs.
By a method according to an aspect of the present invention, a pilot/driver of the vehicle can experience the behaviour of the vehicle in a certain state without actually operating the vehicle in this certain state. Realistic training can be performed to a lower cost while still using a real vehicle. For example, the vehicle can be selected to behave as if the load configuration was different from the actual conditions. In other words; a simulation of a heavily loaded aircraft can be performed by flying an unloaded (light) aircraft. According to an aspect, an unloaded and light aircraft can be caused to behave like it really was loaded and heavy. This in turn can save costs and improve safety.
The method and system according to an aspect of the invention may be used for simulating many different states of the vehicle and/or the environment to provide training situations for a person. The term “a simulated state which is a possible real state of the vehicle and/or the environment” refers to a state which can very well occur during other conditions while using the same vehicle but which state is simulated to avoid operating the vehicle in such a state and still provide the desired training. The term “different states” does not comprise different designs of the vehicle, or other kinds of vehicle, beyond modifications associated to the loading of the vehicle. As an example, the real state of an air vehicle could be an unloaded state and the simulated state of the air vehicle could be a state where the same air vehicle is loaded with weapons, such as missiles or similar. In another example a simulated fuel quantity is different from the actual fuel quantity carried by the vehicle.
Further examples of simulated states are the simulation of a transient disturbance of an air vehicle due to releasing loads although no actual loads are released, and the simulation of special wind and temperature conditions although the actual weather is different. The consequence of the simulated states is that the weight of the simulated vehicle is different from the actual weight of the vehicle, that the centre of gravity of the simulated vehicle is different from the actual centre of gravity of the vehicle and/or that the moment of inertia the simulated vehicle is different from the actual moment of inertia of the vehicle Further consequences may be that the relationship between the angle of attack and sideslip and the drag and lift of the simulated vehicle is different from the actual relationship between said angles and the drag and lift of the vehicle
Particularly, the method according to an aspect of the invention may be used for training a pilot/driver by the simulation of a state, which state is created by controlling dynamic properties of the vehicle and/or controlling an engine of the vehicle, such as the position of one or more air vehicle control surfaces and/or the setting of engine thrust and/or thrust vectoring.
According to an aspect of the invention, the motion of the vehicle in the simulated state is calculated in a first step by using a vehicle model and the vehicle operating commands as input, and then the vehicle command signals are calculated in a second step by using the calculated motion of the vehicle in the simulated state as input to the calculation unit. Hereby, the controller for training mode operation can be designed using the controller for normal mode operation and the equations of motion.
The vehicle model, which can handle different load configurations and environmental conditions for instance, can be either in its simplest form a tabulated vehicle description, but preferably a real time dynamic model for the vehicle motion based on the equations of motion.
The calculated vehicle command signals used for controlling the vehicle are ordinary vehicle control signals and any additional vehicle control signals produced by the training system during training mode only. However, in both cases the calculated vehicle command signals are based on the vehicle operating commands and designed to cause the vehicle to respond to the vehicle operating commands in a way that corresponds to the state simulated by the vehicle model instead of the actual state of the vehicle and/or the environment.
A control unit comprised in the simulation system may be achieved based on known electrical and/or mechanical control components and corresponding software. A computer program comprising an instruction set stored in an internal memory of the computer may be used to instruct a processor for accomplishing the steps of the method when the instruction set is executed in the computer. The computer program can be provided at least partly via a network such as the Internet. The control unit may be designed for receiving a computer readable medium having a stored program or data thereon intended to cause the computer to control the steps of the method according to an aspect of the invention.